Spray nozzles



y 1955 E. s. WIlTA-LA Emu. 2,708,597

SPRAY NOZZLES Filed April 1, 1954 I Edwin S Viifala DonaldJKridel 2! .QINVENTORS I,

BYE

/ ATTORnqYS United States Patent SPRAY NOZZLES Edwin S. Wiitala and Donald J. Kridel, Rochester, N. Y., assignors to Eastman Kodak Company, 'Rochester, N.-Y., a corporation of New Jersey Application April 1, 1954, Serial No. 420,293 3 Claims. (21. 299-59 This invention relates to spray nozzles, and more particularly to an improved nozzle device adapted for use in spraying liquids onto very dusty powders, such as photographic fixing powders, which tend to cake on the spray nozzle and retard its operation. I

Photographic acid fixing powders such as for instance those described in U. S. Patent 2,592,366 of Edwin S. Wiitala and Donald J. Kridel may be prepared by introducing the several components of the mixture in proper proportions into a rotating blender-drier in which the several components are tumbled to produce thorough mixing and drying. During this tumbling some of the finely divided components in the fixing powder tend to form dust in the rotating blender to the disadvantage of the mixing process.

Heretofore an attempt has been made to lay this dust by spraying very fine sprays of water into the rotary blender above the tumbling fixing powders. These fine water sprays produce an agglomeration of the fine dust particles and cause them to be restored to the main bulk of the tumbling powder. The small water content thus taken up by the tumbling powder was dried out or controlled within desired limits by the heat applied to the drier.

However, it was found that an ordinary unprotected spraying nozzle would not function properly for more than about 15 minutes of operation because of the tendency of the dust particles to cake over the fine nozzle orifices. This caking apparently was due to the presence within the rotating drier of turbulent air containing a high concentration of dust and moisture. It also appeared that suction at the vertex of the nozzle tended to draw the dust and moisture to the nozzle helping to cause the caking.

Numerous nozzle protective devices were investigated by the present inventors including flat shields placed near the tip of the nozzle, a protective cup on the nozzle, and a cup having an auxiliary tangential flow of air. The shield was not satisfactory protection, and the cups themselves with or without air became caked over and the nozzles soon became clogged.

An object, therefore, of the present invention is an improved nozzle device which can be employed to spray liquids in a fine spray into a dust filled atmosphere with out the nozzle being caked over by wet dust agglomerations. Other objects will appear hereinafter.

Our invention is further illustrated in the accompanying drawings in which:

Fig. 1 is a side view in elevation and partly in section showing our complete nozzle device;

Fig. 2 is a schematic view partly in section of a rotary blender-drier suitable for drying photographic powders which is equipped with a plurality of nozzle devices constructed in accordance with our invention taken on the lines 22 of Fig. 3;

Fig. 3 is an end view of Fig. 2;

Fig. 4 is an end view of the nozzle device showing the 2,708,597 Patented May 17, 1955 air pipe positioned at a tangent to the cylinder defining the air chamber in the device. 1 In these drawings similar parts are denoted by the same numbers.

Referring to Fig. 1 the structure of our novel nozzle device 10 is shown. This comprises a nozzle head 11 suitably attached'to a liquid supply pipe 12. A cylindri-.

cal member 13 is concentrically positioned in respect to the nozzle 11, the upper end of cylindrical member 13 is closed as shown at 14 and pipe 12 passes through the closed end 14 and is welded thereto as shown at 15.

g The .lower end of the cylinder 13 is open and the nozzle 11 protrudes beyond the cylinder as is clear from Fig. l. A pipe 16 is attached to the side of cylinder 13 through which air under pressure is supplied to the chamber 17 which is formed between the nozzle assembly and cylinder 13. The pipe 16 may be attached to cylinder 13 at a tangent as is shown in Fig. 4 so that the air in chamber 17 as shown by the arrows will tend to swirl around the nozzle 11.

A de-caking member 18 comprising an expandable flexible tube, which can be inflated by air from bulb 19 on from any other suitable source through conduit 21, is positioned around the outside of cylinder 13 at its lower portion. This flexible tube can be made larger if desired so as to cover more of the external surface of the cylinder 13 than is shown in Fig. 1.

The operation of our nozzle device is as follows: Assuming that the nozzle device 10 is positioned in a dust filled atmosphere and air is not flowing through pipe 16, the back suction effects of the spray flowing from the nozzle 11 will permit a build up of accumulated dust to cake over the nozzle and shut off the liquid spray. However, if air under low pressure is flowing through pipe 16 and hence flowing out of the open end of chamber 17 and past the nozzle 11, the back suction effect is overcome and no caking will occur on the nozzle. Caking will occur even under such operation on the outside of cylinder 13. However, since this area is covered by expandable tube 18, the cake will form on the outside of the expandable tube 18. By periodically squeezing bulb 19 the tube 18 can be periodically inflated and deflated so as to crack off the built up cake. In a continuous operation a pulsating air pressure could be employed instead of air pressure from the bulb so as to cause the surface of tube 18 to flex back and forth which would break off the built up cake at desired predetermined intervals.

A practical use of our improved nozzle device may be seen by reference to Figs. 2 and 3. In Fig. 2 there is shown a conventional rotary blender-drier 25 comprising a rotating cylinder 26 in which a fixing powder 27 is being continuously dried. The powder is fed from a source, not shown, by screw 28 through conduit 29. Cylinder 26 is rotated and heated by conventional means not shown. Y

A plurality of nozzle devices 10 each made in accordance with our invention and having the essential parts described in connection with Fig. 1 are positioned above the powder 27 in cylinder 26. Preferably they are positioned at an angle with respect to the perpendicular as shown in Fig. 3. The liquid spray from the plurality of nozzles 10 will tend to lay the dust rising from the dried tumbled powder which is continuously passing through the drier. The flexible tubes 18 in this case are periodically inflated by pulsating air pressure through pipe 21 from a source, not shown, so as to break off the dust cake formed thereon. Air flowing from pipe 16 to the respective chamber 17 also prevents formation of a dust cake over the nozzles due to suction eifects.

Cur novel nozzle device permits the operation of such rotary blender driers for long periods of time and hence greatly increases the economies of operation of such drying and mixing processes.

We claim:

1. A nozzle device adapted for continuous spraying of liquids in a dust filled atmosphere comprising in combination a member forming a chamber having an open end, a nozzle pointing out of said chamber, means for supplying liquid to said nozzle to be sprayed, means for supplying air under pressure to said chamber, inflatable means positioned around the outside of the chamber, and means for inflating said inflatable means.

2. A nozzle device adapted for continuous spraying of liquids in a dust filled atmosphere comprising in combination a cylindrical member forming a chamber having a closed end and an open end, a nozzle concentrically positioned in said chamber and extending out of said chamber through said open end, means for supplying liquid to said nozzle 10 be sprayed, means for supplying air under pressure to said chamber, inflatable means positioned around the outside'of the chamber, and means for inflating said inflatable means.

3.- A nozzle device adapted for continuous spraying of liquids in a dust filled atmosphere comprising in combination a cylindrical metal member forming a chamber, having a closed end and an open end, a nozzle concentrically positioned in said chamber and extending out of said chamber through said open end, pipe means passing through the closed end of said metal member for supplying liquid to said nozzle to be sprayed, means for supplying air under pressure to said chamber, an inflatable tube positioned around theoutside of the chamber, and means for inflating said inflatable tube.

No references cited. 

1. A NOZZLE DEVICE ADAPTED FOR CONTINUOUS SPRAYING OF LIQUIDS IN A DUST FILLED ATMOSPHERE COMPRISING IN COMBINATION A MEMBER FORMING A CHAMBER HAVING AN OPEN END, A NOZZLE POINTING OUT OF SAID CHAMBER, MEANS FOR SUPPLYING LIQUID TO SAID NOZZLE TO BE SPRAYED, MEANS FOR SUPPLYING AIR UNDER PRESSURE TO SAID CHAMBER, INFLATABLE MEANS POSITIONED AROUND THE OUTSIDE OF THE CHAMBER, AND MEANS FOR INFLATING SAID INFLATABLE MEANS. 